Definition
A line drawn on an instrument approach chart or en route chart that depicts the published path an aircraft is expected to follow, connecting fixes, navaids, or waypoints along an airway, transition, feeder route, or approach segment.
Plain English
The line printed on a chart that shows the path you are supposed to fly between two points.
Context Anchor
Seen in instrument procedure and en route discussions when sectors, protected areas, or obstacle clearance are described in relation to a route.
Derivation
From Old French 'route' meaning a way or course traveled. On a chart, the 'route line' is literally the drawn line showing that course.
Why Pilots Care
Ensures the aircraft follows a safe, cleared path avoiding obstacles and terrain while complying with ATC instructions.
Analogy
Think of it like the centerline of a road lane. The allowed space extends out from that line, but the line itself shows the intended path.
Intuition Check
Do not read route line as just any drawn line on a map. Here it means the intended course line used as a reference for route protection and sector layout.
Example Sentence 1
After crossing the initial approach fix, the pilot followed the route line inbound to the final approach course.
Example Sentence 2
Deviating from the route line without clearance can result in terrain conflicts in mountainous sectors.